MAN 469 



making of implements, of dwellings, and getting numerous forms 

 of mastery over nature. The brain working through language 

 and in the more intimate parental relations brought about by 

 homes, makes possible education and the training of the young 

 in the discoveries of the race. The increase of the cerebral 

 cortex and the closer association of the different parts of this 

 cortex are in some way related to the better consciousness and 

 memory in man. The use of language has been the great in- 

 strument whereby the power of abstract reasoning has been 

 developed, and this has produced a further increase in size and 

 complexity of the brain. 



470. Mental Life of Man, Habits, Instincts, Reason. 



Fundamentally, the mental life of man, no less than that of the 

 lower animals, is the function of the brain and its accompanying 

 systems of organs. Like that of all the other animals, much of 

 man's life and activities is made up of habitual actions that have 

 been acquired through trial and experience, and the crystallizing 

 of these through memory. The child takes its first steps in 

 learning very much as the lower animals do. It is stimulated 

 and it acts somewhat at random. If satisfaction follows the 

 action it is repeated. If dissatisfaction follows, some other 

 action is tried. Finally it hits upon a suitable action. This is. 

 the trial and error method. 



Much of it, quite as really as in the lower animals, is of those 

 more mysterious impulses (instincts) that we do not get by our 

 own experiences, but which belong to our make-up in some way 

 as an inheritance from the past of our ancestors. We do not 

 realize how much of our own life is controlled by these inherited 

 instincts. These instincts predispose us to do certain things. 

 The mind of man, working upon these experiences and internal 

 feelings, and using language to make clear to others his states 

 and to convince them of his conclusions, has reached what may 

 well be regarded as the highest human power that of abstract 

 reasoning: of saying, (i) this is true; and (2) this is true; (3) 

 therefore, this is true. The study of this feature of Zoology is 

 known as Psychology. The lower animals have their psychology 

 as well as man, but it is not so far-reaching nor complex. 



